Xamarin形成DisplayActionSheet外部触摸错误

Question

在从列表视图中删除项目之前，我有一个Displayactionsheet供确认。

var action = await DisplayActionSheet("Delete Item !", "Yes", "No", "Press YES to delete item");
        Debug.Write(action);
        if (action.Equals("Yes"))
        {
            var image = sender as ImageButton;
            var item = image?.BindingContext as Product_Value2;
            var vm = BindingContext as ItempageVM;
            vm?.Delete.Execute(item);

        }
        else if (action.Equals("No"))
        {

        }

如果我选择“是”或“否”，则我得到了期望的结果。当我在此框外按下时，显示此错误：

Attempted to finish an input event but the input event receiver has already been disposed.
Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object.

如何处理此异常？

Answer 1

如果您在外面按，则动作为null，因此您可以检查null并做您想做的事

        var action = await DisplayActionSheet("Delete Item !", "Yes", "No", "Press YES to delete item");

        if(action == null)
        {
           //Your logic here
        }
        else if (action.Equals("Yes"))
        {
            var image = sender as ImageButton;
            var item = image?.BindingContext as Product_Value2;
            var vm = BindingContext as ItempageVM;
            vm?.Delete.Execute(item);

        }
        else if (action.Equals("No"))
        {

        }